1. Field of Invention
The invention relates to a sewing machine. Particularly, to a sewing machine that sets the sewing conditions, such as the stitch width, stitch length, and thread tension, for each stitch pattern and rewritably stores the set sewing conditions in a non-volatile memory in correspondence with each stitch pattern.
2. Description of Related Art
A conventional sewing machine with a display commonly displays various types of sewable stitch patterns to allow an operator to select a desired stitch pattern therefrom, as a stitch pattern to be sewn, and also displays at least part of the selected stitch pattern or the name of the selected stitch pattern to notify the operator of the selected stitch pattern.
An electronically controlled sewing machine of this kind is widely available and is designed to display, on a display, the sewing conditions (stitch width, stitch length, thread tension, and the like) for a selected stitch pattern if it is a utility stitch pattern, such as a straight stitch pattern or a zigzag stitch pattern, in order to allow an operator to set the sewing conditions using sewing condition setting keys.
As shown in FIG. 13, a sewing machine the applicants have put to practical use has a display 100 and a plurality of touch keys provided on the surface of the display 100. The functions of the touch keys are displayed on the display 100. For example, when a zigzag pattern key 102 is pressed on a utility stitch pattern selection screen 101, a zigzag stitch pattern is selected as the stitch pattern to be sewn.
Then, at the top of the display 100, a horizontal zigzag stitch pattern and the stitch pattern name "Zigzag (C)" are displayed. Also, below a plurality of stitch patterns, as displayed on the display 100, the stitch width "7.0 mm", the stitch length "2.5 mm", and the thread tension "5" are displayed as the sewing conditions of the selected zigzag stitch pattern. The thread tension "5" represents the fifth level from the weakest level on a 1-to-9 scale, and is indicated by an illuminating indicator lamp that is the fifth from one end of a row of nine indicator lamps.
Default values for the sewing conditions for various types of stitch patterns are prestored in a ROM of a control unit. Assuming that FIG. 13 shows a screen displayed immediately after a zigzag stitch pattern has been selected, the stitch width "7.0 mm", the stitch length "2.5 mm", and the thread tension "5" are displayed as the sewing condition default values for the zigzag stitch pattern.
On the utility stitch pattern selection screen 101, a plurality of touch sewing condition setting keys 103a, 103b, 104a 104b, 105a-105c are provided to allow an operator to change the sewing condition default values to desired values.
As described above, in the conventional electronically controlled sewing machine, the sewing condition default values are read from the ROM each time a stitch pattern is selected, and an operator uses the sewing condition setting keys to change the sewing condition default values to desired values. As desired sewing conditions are hard to set only by judging from the displayed sewing conditions, the sewing conditions are set, in many cases, and a trial sewing is then performed.
In the conventional electrically controlled sewing machine, the sewing condition default values stored in the ROM are set as the sewing conditions, each time a stitch pattern is selected. Thus, even when the sewing condition for a certain stitch pattern has been set as desired, the set sewing conditions cannot be used when the same stitch pattern is selected later.
The sewing conditions previously set for a certain stitch pattern are often desired to be used again when the same stitch pattern is selected. In such a case, however, the desired sewing conditions must be set again, using the sewing condition setting keys to change the sewing condition default values. Trial sewing must then be again performed if needed to verify the stitch is as desired. This procedure is very tedious.
On the other hand, because the sewing condition default values for a stitch pattern are normally set to be optimal values so as to provide preferable conditions for sewing the stitch pattern, there is a case where the sewing conditions changed for a certain stitch pattern are desired to be reset to the default values when the same stitch pattern is selected later.
Japanese Laid-open Patent Publication No. 5-228275 discloses an embroidery machine in which its operating environment is set and registered in an EEPROM for each operator or for each machine part condition, and the operating environment is suitably set by selecting the operator or the machine part condition to be used. In this embroidery machine, however, the sewing conditions cannot be set for each stitch pattern.